Map Nasa Heightmap to Sphere
Try this. 1. Apply scale and rotation of the object. Activate the object than press Ctrl + A button, than choose scale and rotation. 2. Unwrap the object perfectly to a rectangular shape. Delete top and bottom vertices. than make one vertical markseam, than unwrap the sphere. please learn how to unwrap UV sphere, in somewhere tutorial. 3. add more polygon, increase subdivision surface to highest level. if needed add double subdivision surface modifier, more polygon more detai.